Continuous efforts are being made to increase the safety of the passengers in an aircraft when a fire should start. Especially after a forced landing, there is a substantial fire danger caused by aircraft fuel flowing out of broken fuel lines or tanks. If an aircraft stands or lies with its body in a burning pool of aircraft fuel, it takes conventionally less than a minute for the outer skin of the aircraft to burn through at least at the most exposed points. Thus, it is necessary that the interior wall of the aircraft body that encloses the cabin must retard the fire at least as long as it takes for the passengers to leave the aircraft. It has been found that in a fire situation as just described the windows and the areas around the windows in the cabin walls are weak points which do not retard the fire as long as is necessary for the above purpose. The window panes are conventionally made of synthetic material that has hardly any fire retarding ability.